US11943555B2 - Pixel processing circuit and reading method thereof, and image sensor - Google Patents
Pixel processing circuit and reading method thereof, and image sensor Download PDFInfo
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- US11943555B2 US11943555B2 US17/976,903 US202217976903A US11943555B2 US 11943555 B2 US11943555 B2 US 11943555B2 US 202217976903 A US202217976903 A US 202217976903A US 11943555 B2 US11943555 B2 US 11943555B2
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- 238000012545 processing Methods 0.000 title claims abstract description 42
- 238000000034 method Methods 0.000 title claims abstract description 19
- 238000012546 transfer Methods 0.000 claims description 21
- 230000002146 bilateral effect Effects 0.000 claims description 7
- 238000004891 communication Methods 0.000 claims description 4
- 238000013139 quantization Methods 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 7
- 238000013461 design Methods 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 230000010354 integration Effects 0.000 description 4
- 238000003491 array Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 239000003086 colorant Substances 0.000 description 2
- 230000014509 gene expression Effects 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/70—SSIS architectures; Circuits associated therewith
- H04N25/76—Addressed sensors, e.g. MOS or CMOS sensors
- H04N25/77—Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components
- H04N25/772—Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components comprising A/D, V/T, V/F, I/T or I/F converters
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/10—Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from different wavelengths
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/70—SSIS architectures; Circuits associated therewith
- H04N25/71—Charge-coupled device [CCD] sensors; Charge-transfer registers specially adapted for CCD sensors
- H04N25/75—Circuitry for providing, modifying or processing image signals from the pixel array
Definitions
- the present invention relates to the field of integrated circuit design, in particular to a pixel processing circuit applied in a CMOS image sensor, a reading method thereof and an image sensor.
- CMOS Image Sensors have been widely used in imaging fields such as video, surveillance, industrial manufacturing, automobiles, and home appliances.
- the mainstream readout circuit configuration of a CIS is based on a column-level analog-to-digital converter (ADC) to ensure that the CIS has enough conversion accuracy and speed under reasonable power consumption.
- ADC analog-to-digital converter
- the pixel size is small, it is impossible to achieve that one ADC column corresponds to one pixel column by adopting the parallel column ADC readout structure with single-sided arrangement, so this design can only be achieved by adopting the parallel column ADC readout structure with bilateral arrangement on the pixel array. This bilateral arrangement of two ADC arrays cannot avoid a mismatch, which results in a fixed parity column difference.
- the present invention provides a pixel processing circuit, a reading method thereof and an image sensor, which can eliminate the difference between the Gr channel and the Gb channel, thereby avoiding the appearance of “maze pattern” in an image.
- the present invention provides a pixel processing circuit and a reading method thereof, an image sensor.
- a switch selection module between a pixel array and an ADC module, and by controlling the state of the switch selection module, the pixel signals passing through the Gr channel and the Gb channel are read by the ADCs on a same side of the pixel array, ensuring that the pixel signals of the Gr channel and the Gb channel do not have value deviation, thereby avoiding the phenomenon of “maze pattern” after image interpolation and ensuring image quality.
- the present invention provides a pixel processing circuit configured for being applied to an image sensor of a bilateral parallel ADC readout architecture, the circuit comprising: a plurality of pixel units arranged in a Bayer array, an Analog-to-Digital Converter (ADC) module comprising a plurality of analog-to-digital converters, and a plurality of switch selection modules, the number of the switch selection modules set to be half of the number of the analog-to-digital converters;
- ADC Analog-to-Digital Converter
- the present invention has the advantages that by controlling the state of the switch selection modules, the present invention achieves the ADC conversion of the pixel signals passing through the Gr channel and the Gb channel through the same side of the pixel array, ensuring that the pixel signals of the Gr channel and the Gb channel do not have value deviation, thereby avoiding the phenomenon of “maze pattern” after image interpolation and ensuring image quality.
- each of the switch selection modules comprises a plurality of switching circuits at least including a first switching circuit, a second switching circuit, a third switching circuit and a fourth switching circuit; wherein a number of columns of the pixel array is even, the first switching circuit and the second switch circuit are located at the first side of the pixel array and the third switching circuit and the fourth switching circuit are located at the second side of the pixel array; the pixel units in each of odd-numbered columns of the pixel array are respectively electrically connected to one end of the first switching circuit, and are respectively electrically connected to one end of the third switching circuit of the switch selection module; the pixel units in each of even-numbered columns of the pixel array are respectively electrically connected to one end of the second switching circuit of the switch selection module, and are respectively electrically connected to one end of the fourth switching circuit of the switch selection module; wherein another ends of adjacent first switching circuit and second switching circuit are electrically connected to the common first analog-to-digital converter, another ends of adjacent third switching circuit and fourth switching circuit are electrically connected to the common second
- the first switching circuit includes at least one switch
- the second switching circuit includes at least one switch
- the third switching circuit includes at least one switch
- the fourth switching circuit includes at least one switch
- each column of pixel units is connected to a corresponding switching circuit through an output bus.
- the pixel unit includes a photodiode, a transfer transistor, a reset transistor, a source-follower transistor, and a row selection transistor; one end of the photodiode is grounded, and the other end of the photodiode is connected to a drain of the transfer transistor; a gate of the transfer transistor is configured for accessing a TX signal, a source of the transfer transistor is connected to a drain of the reset transistor, and a gate of the source-follower transistor; a source of the reset transistor is configured for accessing a power supply signal, and a gate of the reset transistor is configured for accessing an RX signal; a source of the source-follower transistor is configured for accessing the power supply signal, a drain of the source-follower transistor is connected to a source of the row selection transistor, a gate of the row selection transistor is configured for accessing an SEL signal, and a drain of the row selection transistor is connected to the output bus of the pixel unit; wherein the drain of the reset transistor is connected to the source of the source of
- the analog-to-digital converter includes a comparator and a counter electrically connected to the comparator.
- the present invention provides a reading method of a pixel processing circuit, being applied to the pixel processing circuit in the second item of the first aspect, including:
- the conduction state of the switch selection module includes: at a time of a read phase, a first switching circuit and a fourth switching circuit of the switch selection module being in a same conduction state, a second switching circuit and a third switching circuit being in the same conduction state, the first switching circuit and the third switching circuit being in opposite conduction states, and the conduction state of the switch selection module being opposite when reading odd-numbered rows and even-numbered rows of the pixel array.
- the present invention provides an image sensor including: the pixel processing circuit as described in any one of the first aspect; a control logic module for controlling the pixel processing circuit to process a pixel signal; and a data processing module for obtaining a signal processed by the pixel processing circuit.
- FIG. 1 is an overall circuit configuration diagram of a CMOS image sensor
- FIG. 2 is a schematic diagram of a CIS readout circuit architecture
- FIG. 3 is a schematic diagram of another CIS readout circuit architecture
- FIG. 4 is a schematic diagram of a pixel array based on a Bayer pattern
- FIG. 5 is a schematic structural diagram of a pixel processing circuit according to an embodiment of the present invention.
- FIG. 6 is a circuit configuration diagram of a CIS standard four-transistor pixel unit.
- FIG. 7 is an operation timing diagram of an CIS standard four-transistor pixel unit.
- a and/or B can represent the case where A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural.
- the character “/” generally indicates that the related objects are an alternative relationship.
- references to “one embodiment” or “some embodiments” or the like described in the description are intended to include in one or more embodiments of the present application particular features, structures, or features described in conjunction with the embodiment. Thus, statements “in one embodiment,” “in some embodiments,” “in other embodiments,” “in yet other embodiments,” and the like appearing in differences in the description do not necessarily all refer to the same embodiment, but mean “one or more but not all embodiments,” unless otherwise specifically emphasized.
- the terms “including”, “comprising”, “having” and variations thereof all mean “including but not limited to”, unless otherwise specifically emphasized.
- connection includes direct connection and indirect connection, unless otherwise stated.
- the terms “first”, “second” are for descriptive purposes only and cannot be construed as indicating or implying relative importance or implying the number of the indicated technical features.
- the words “exemplary” or “for example” are used as examples, illustrations, or description. Any embodiment or design described as “exemplary” or “for example” in embodiments of the present application should not be construed as being more preferred or advantageous than other embodiments or designs. Rather, the use of the words “exemplary” or “for example” is intended to present related concepts in a concrete manner.
- FIG. 1 the overall circuit configuration of the CMOS image sensor is shown in FIG. 1 .
- the circuit configuration consists of a pixel array, a column ADC module, a column memory unit (not shown in FIG. 1 ), a data processing section and a control logic section.
- the pixel array is composed of several pixel units, and the pixel units convert photocharges into analog voltage quantity after photosensing.
- the pixel signals of the pixel units in each column of the pixel array are converted from analog to digital by the corresponding ADC in the column ADC module, and then the subsequent data processing is carried out.
- There are M+1 columns of pixel array in FIG. 1 corresponding to M+1 ADCs, which can be ADC ( 0 ), ADC ( 1 ), . . . , ADC (M), that is, each column in the pixel array corresponds to one ADC.
- each ADC corresponds to the output of a column of pixels
- a pitch size (PZ) of each ADC in the column ADC module is exactly the same as a pitch size of each column of pixel units in the pixel array.
- PZ pitch size
- the ADCs in the column ADC module are arranged on both sides of the pixel array, as shown in FIG. 3 .
- the ADCs are arranged on both sides of the pixel array, the deviation in process conditioning and power supply on both sides of the pixel array will lead to a slight difference between the ADCs on both sides, which is fixed for the same CIS chip. If the light is uniformly distributed, there will be a difference between the ADCs on both sides of the pixel array. That is, as shown in FIG. 3 , there is a fixed deviation between the pixel signal output through the Gr channel in the even-numbered column and the pixel signal output through the Gb channel in the odd-numbered column.
- the Gr channel refers to a channel formed by a green pixel unit Gr and a transmission bus connected to the pixel.
- the Gb channel refers to a channel formed by a green pixel Gb and a transmission bus connected to the pixel.
- the general filter implementation of the CIS is based on a Bayer pattern, that is, RGB pattern including R (red), B (blue), Gr (green) and Gb (green) components. After normal illumination coming in, different colors of light will pass through the color filter, which makes R light, G light and B light reach the CIS, respectively. Then the CIS completes the conversion from illumination intensity to digital quantity, and then synthesizes the final image through the corresponding interpolation algorithm.
- FIG. 4 shows a simple Bayer pattern-based pixel array including a red pixel unit Gr, a green pixel unit Gb, a red pixel unit R and a blue pixel unit B (not labeled as shown in FIG. 4 ). As shown in FIG.
- the present invention provides a pixel processing circuit, which is applied to an image sensor of a bilateral parallel ADC readout architecture, the circuit comprises a plurality of pixel units arranged in a Bayer array, an Analog-to-Digital Converter (ADC) module comprising a plurality of analog-to-digital converters, and a plurality of switch selection modules.
- ADC Analog-to-Digital Converter
- the number of the switch selection modules is set to be half of the number of the analog-to-digital converters. In other embodiments, the number of the switch selection modules can be irrelated to that of the switch selection modules. In the embodiment as shown in FIG.
- the plurality of analog-to-digital converters comprises first analog-to-digital converters located on a first side of the pixel array and second analog-to-digital converters located on a second side of the pixel array opposite to the first side.
- Each of the switch selection modules is configured to have a first unit disposed between the first side of the pixel array and one of the first analog-to-digital converters, and a second unit disposed between the second side of the pixel array and one of the second analog-to-digital converters.
- the switch selection modules are configured to switch the communication between the pixel units and the first and second analog-to-digital converters on the opposite first and second sides of the pixel array, such that signals of green pixel units are read by the first analog-to-digital converters located at the first side of the pixel array, such as ADC ( 0 ), ADC ( 2 ), ADC ( 4 ), . . . ADC (n ⁇ 1), and signals of remaining color pixel units are read by the second analog-to-digital converters located at the second side of the pixel array such as ADC ( 1 ), ADC ( 3 ), ADC ( 5 ), . . . ADC (n).
- the present invention achieves the ADC conversion of the pixel signals passing through the Gr channel and the Gb channel through the same side of the pixel array, ensuring that the pixel signals of the Gr channel and the Gb channel do not have value deviation, thereby avoiding the phenomenon of “maze pattern” after image interpolation and ensuring image quality.
- the switch selection module comprising a plurality of switching circuits at least including a first switching circuit, a second switching circuit, a third switching circuit and a fourth switching circuit; wherein a number of columns of the pixel array is even, the first switching circuit and the second switch circuit are located at the first side of the pixel array and the third switching circuit and the fourth switching circuit are located at the second side of the pixel array; the pixel units in each of the odd-numbered columns of the pixel array are respectively electrically connected to one end of the first switching circuit of the switch selection module, and are respectively electrically connected to one end of the third switching circuit of the switch selection module; the pixel units in each of the even-numbered columns of the pixel array are respectively electrically connected to one end of the second switching circuit of the switch selection module, and are respectively electrically connected to one end of the fourth switching circuit of the switch selection module; wherein another ends of adjacent first switching circuit and second switching circuit are electrically connected to a common first analog-to-digital converter such as ADC ( 0 ), another ends of adjacent first switching
- the first switching circuit includes at least one switch
- the second switching circuit includes at least one switch
- the third switching circuit includes at least one switch
- the fourth switching circuit includes at least one switch
- each column of pixel units is connected to a corresponding switching circuit through an output bus.
- the output bus branches can be connected to a common bus via the switching circuits S 0 , S 1 , S 2 and S 3 as shown in FIG. 5 . That is to say, each column of pixel units is connected to an output bus branch, which is electrically connected to an end of each of the switching circuits S 0 , S 1 , S 2 and S 3 .
- the output bus branches can be connected to a common bus such as PIX_OUT ( 0 ), PIX_OUT ( 2 ), . . . , PIX_OUT(n ⁇ 1), and PIX_OUT ( 1 ), PIX_OUT ( 3 ), . . . , PIX_OUT (n).
- the pixel unit includes a photodiode, a transfer transistor, a reset transistor, a source-follower transistor, and a row selection transistor; one end of the photodiode is grounded, and the other end of the photodiode is connected to a drain of the transfer transistor; a gate of the transfer transistor is configured for accessing a TX signal, a source of the transfer transistor is connected to a drain of the reset transistor, and a gate of the source-follower transistor; a source of the reset transistor is configured for accessing a power supply signal, and a gate of the reset transistor is configured for accessing an RX signal; a source of the source-follower transistor is configured for accessing the power supply signal, a drain of the source-follower transistor is connected to a source of the row selection transistor, a gate of the row selection transistor is configured for accessing an SEL signal, and a drain of the row selection transistor is connected to the output bus of the pixel unit; wherein the drain of the reset transistor is connected to the source of the source of
- the analog-to-digital converter includes a comparator and a counter electrically connected to the comparator.
- a pixel processing circuit applied to an image sensor of a bilateral parallel ADC readout architecture includes a pixel array composed of pixel units, an ADC module composed of n+1 analog-to-digital converters, and a plurality of switch selection modules, where n is an odd number greater than or equal to 1.
- Each of the switch selection modules includes a first switching circuit S 0 , a second switching circuit S 1 , a third switching circuit S 3 and a fourth switching circuit S 2 .
- the ADC module includes first analog-to-digital converters disposed on a first side of the pixel array and second analog-to-digital converters disposed on an opposite second side of the pixel array; wherein the number of columns of the pixel array is n+1; the pixel units in each of the odd-numbered columns of the pixel array are respectively electrically connected to one end of the first switching circuit S 0 and electrically connected to one end of the third switching circuit S 3 . That is to say, the pixel units in each of the odd-numbered columns are electrically connected to only one first switching circuit S 0 and only one third switching circuit S 3 .
- the pixel units in each of the even-numbered columns of the pixel array are respectively electrically connected to one end of the second switching circuit S 1 , and are respectively electrically connected to one end of the fourth switching circuit S 2 . That is, the pixel units in each of the even-numbered columns are electrically connected to only one second switching circuit S 1 and only one fourth switching circuit S 2 .
- the ADC module includes: ADC ( 0 ), ADC ( 1 ), ADC ( 2 ), ADC ( 3 ), . . .
- ADC (n ⁇ 1), ADC (n), and the first analog-to-digital converters of ADC ( 0 ), ADC ( 2 ), . . . , ADC (n ⁇ 1), and the second analog-to-digital converters of ADC ( 1 ), ADC ( 3 ), . . . ADC (n) are respectively arranged on both sides of the pixel array.
- the present invention also provides a reading method of the pixel processing circuit, which includes: performing row-by-row reading and quantization processing for pixel units in a pixel array according to a row selection control signal, including:
- the conduction state of the switch selection module includes: at a time of a read phase, a first switching circuit and a fourth switching circuit of the switch selection module being in a same conduction state, a second switching circuit and a third switching circuit being in the same conduction state, the first switching circuit and the third switching circuit being in opposite conduction states, and the conduction state of the switch selection module being opposite when reading odd-numbered rows and even-numbered rows of the pixel array.
- the readout process of pixel signals related to different colors in the pixel array is explained by the operation principle of the first switching circuit S 0 , the second switching circuit S 1 , the third switching circuit S 3 and the fourth switching circuit S 2 .
- the pixel array in FIG. 5 includes green pixel units Gr, green pixel units Gb, red pixel units R, and blue pixel units B arranged in Bayer pattern.
- a state of a control signal of the first switching circuit S 0 is “high”, the first switching circuit S 0 is turned on.
- the state of the control signal of the first switching circuit S 0 is “low”, the first switching circuit S 0 is turned off.
- the second switching circuit S 1 , the fourth switching circuit S 2 , and the third switching circuit S 3 are turned on and off in the same way.
- the first row of pixel units of the pixel array includes green pixel units Gb and blue pixel units B.
- the transfer transistor is turned off, firstly, the first switching circuit S 0 and the fourth switching circuit S 2 are controlled to be turned off, the second switching circuit S 1 and the third switching circuit S 3 are turned on, a reset signal of the blue pixel unit B is read out as B_VRST by ADC ( 1 ), and a reset signal Gb_VRST of the green pixel unit Gb is read out by ADC ( 0 ).
- the state of the first switching circuit S 0 , the second switching circuit S 1 , the fourth switching circuit S 2 and the third switching circuit S 3 is controlled to remain unchanged and the TX signal becomes “high”, the transfer transistor is turned on, and an integration signal Gb_VSIG of the green pixel unit Gb is read out by the ADC ( 0 ), and an integration signal B_VSIG of the blue pixel unit B is read out by the ADC ( 1 ). It can be seen that the pixel signal passing through the Gb channel electrically connected to the second switching circuit S 1 is read out by the ADC ( 0 ).
- the pixel signals of the first row of pixel units are continued to be read, the pixel signals of the green pixel units Gb are respectively read by the first analog-to-digital converters of ADC ( 0 ), ADC ( 2 ), ADC ( 4 ), . . . ADC (n ⁇ 1), while the pixel signals of the blue pixel units B are respectively read by the second analog-to-digital converters of ADC( 1 ), ADC ( 3 ), ADC ( 5 ), . . . ADC (n).
- the switch selection module need to be controlled and adjusted so that the conduction states of the first switching circuit S 0 , the second switching circuit S 1 , the fourth switching circuit S 2 and the third switching circuit S 3 are reversed, so that the pixel signals of the green pixel units of a next row are also read out by the first analog-to-digital converters.
- the first switching circuit S 0 and the fourth switching circuit S 2 are controlled to be turned on, the second switching circuit S 1 and the third switching circuit S 3 are turned off, the reset signal of the red pixel unit R is read out as R_VRST by ADC ( 1 ), and the reset signal Gr_VRST of the green pixel unit Gr is read out by ADC ( 0 ).
- the state of the first switching circuit S 0 , the second switching circuit S 1 , the fourth switching circuit S 2 and the third switching circuit S 3 is controlled to remain unchanged and the TX signal becomes “high”, the transfer transistor is turned on, and an integration signal Gr_VSIG of the green pixel unit Gr is read out by the ADC ( 0 ), and an integration signal R_VSIG of the red pixel unit R is read out by the ADC ( 1 ).
- the pixel signals of the second row of pixel units are continued to be read, and the signals of the green pixel units Gr are respectively read by the first analog-to-digital converters of ADC ( 0 ), ADC ( 2 ), ADC ( 4 ), . . .
- ADC (n ⁇ 1) while the signals of the red pixel units R are respectively read by the second analog-to-digital converters of ADC ( 1 ), ADC ( 3 ), ADC ( 5 ), . . . ADC (n).
- the above timing control method can ensure that the pixel signals of Gr channel and Gb channel are read out by ADCs on the same side of pixel array, and the difference between Gr channel and Gb channel due to reading out by different ADC arrays as in the traditional bilateral parallel ADC architecture in FIG. 3 will not occur.
- the red pixel units and the blue pixel units can be read out by the second analog-to-digital converters such as ADC ( 1 ), ADC ( 3 ), ADC ( 5 ), . . .
- ADC (n) signals of the remaining color pixel units connected to a same switch selection module can be read out by a common analog-to-digital converter such as ADC ( 1 ), ADC ( 3 ), ADC ( 5 ), . . . ADC (n).
- the pixel processing circuit comprises a switch selection module and a plurality of analog-to-digital converters.
- the plurality of analog-to-digital converters comprise at least one first analog-to-digital converter such as ADC ( 0 ) located on a first side of the pixel array and at least one second analog-to-digital converter such as ADC ( 1 ) located on a second side of the pixel array opposite to the first side
- the switch selection module is configured to have a first unit disposed between the first side of the pixel array and the at least one first analog-to-digital converters such as ADC ( 0 ), and a second unit disposed between the second side of the pixel array and the at least one second analog-to-digital converters such as ADC ( 1 ), wherein the switch selection module is configured to switch the communication between the pixel units and the first and second analog-to-digital converters on the opposite first and second sides of the pixel array, such that a signal or signals of green pixel units is read by the
- a signal or signals of green pixel units can be read out by the common first analog-to-digital converter such as ADC ( 0 ) that is located at the first side of the pixel array, while a signal or signals of remaining color pixel units such as the red pixel units and/or the blue pixel units can be read out by the common second analog-to-digital converter such as ADC ( 1 ) that is located at the second side of the pixel array.
- ADC first analog-to-digital converter
- ADC ( 1 ) the common second analog-to-digital converter
- FIG. 6 is a circuit configuration of a CIS standard four-transistor pixel unit, which is composed of a photodiode PD, a transfer transistor Mtg, a reset transistor Mrst, a source-follower transistor Msf, and a row selection transistor Msel.
- One end of the photodiode PD is grounded, and the other end of the photodiode PD is connected to the drain of the transfer transistor Mtg.
- a gate of the transfer transistor Mtg is configured for accessing a TX signal, a source of the transfer transistor Mtg is connected to a drain of the reset transistor Mrst, and a gate of the source-follower transistor Msf.
- a source of the reset transistor Mrst is configured for accessing a power supply signal, and a gate of the reset transistor Mrst is configured for accessing an RX signal.
- a source of the source-follower transistor Msf is configured for accessing the power supply signal, a drain of the source-follower transistor Msf is connected to a source of the row selection transistor Msel, a source of the row selection transistor Msel is configured for accessing an SEL signal, and a drain of the row selection transistor Msel is connected to the output of the pixel array.
- the PD generates photoelectrons proportional to the intensity of light when it is sensitized.
- the function of Mtg is to transfer photoelectrons in the PD.
- the Mtg When the TX signal is at high potential, the Mtg is turned on to transfer photoelectrons in the PD to a floating node FD.
- the Mrst plays a role in resetting the FD when the RX signal is at high potential.
- the Msf is an amplifier tube.
- the Msel When the SEL signal is at high potential, the Msel is turned on, and the Msf and the Msel form a path between the current source and ground, at which time, the output of the Msf follows the change of potential of the FD.
- FIG. 7 shows the operation timing of CIS standard four-transistor pixel unit, including phases of resetting (Rst), exposing (Exp) and signal reading (Read).
- Rst resetting
- Exp exposing
- Read signal reading
- the TX signal and RX signal are at “high” potential
- both the Mtg and the Mrst are turned on
- the FD is reset and its potential is pulled up to the power supply voltage VDD.
- the RX signal and the TX signal change to “low” potential, and enter the Exp phase, where PD senses light and accumulates electrons.
- the Read phase the SEL signal is at “high” potential
- the RX signal is at “high” potential first and is then pulled to “low” potential after the FD is reset, and the TX signal is kept at “low” potential.
- the Msf is controlled by the potential of the FD and outputs reset potential VRST through the PIX_OUT.
- the TX signal is pulled to the “high” potential, and electrons on the PD are transferred to the FD.
- the Msf is controlled by the potential of the FD and outputs integrated potential VSIG through the PIX_OUT.
- the difference between VRST and VSIG is the analog voltage corresponding to photoelectrons on the PD.
- the embodiment of the present application provides an image sensor, including: the pixel processing circuit described in any one of the above embodiments; a control logic module for controlling the pixel processing circuit to process a pixel signal; and a data processing module for obtaining a signal processed by the pixel processing circuit.
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Abstract
Description
-
- the plurality of analog-to-digital converters comprising first analog-to-digital converters located on a first side of the pixel array and second analog-to-digital converters located on a second side of the pixel array opposite to the first side, each of the switch selection modules configured to have a first unit disposed between the first side of the pixel array and one of the first analog-to-digital converters, and a second unit disposed between the second side of the pixel array and one of the second analog-to-digital converters;
- wherein the switch selection modules are configured to switch the communication between the pixel units and the first and second analog-to-digital converters on the opposite first and second sides of the pixel array, such that signals of green pixel units are read by the first analog-to-digital converters, and signals of remaining color pixel units are read by the second analog-to-digital converters.
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- performing row-by-row reading and quantization processing for pixel units in a pixel array according to a row selection control signal, including:
- adjusting a conduction state of each switch selection module so that pixel signals of green pixel units and pixel signals of remaining color pixel units in each row of the pixel array are respectively read by the analog-to-digital converters located at different sides of the pixel array while pixel signals of the green pixel units in different rows of the pixel array are read by the analog-to-digital converters located at a same side of the pixel array;
- the remaining color pixel units being red pixel units and/or blue pixel units.
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- adjusting a conduction state of each switch selection module so that pixel signals of green pixel units and pixel signals of remaining color pixel units in each row of the pixel array are respectively read by the analog-to-digital converters located at different sides of the pixel array while pixel signals of the green pixel units in different rows of the pixel array are read by the analog-to-digital converters located at a same side of the pixel array;
- the remaining color pixel units being red pixel units and/or blue pixel units.
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CN202210607372.5A CN115002371A (en) | 2022-05-31 | 2022-05-31 | Pixel processing circuit, reading method thereof and image sensor |
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CN108398243A (en) | 2018-02-28 | 2018-08-14 | 京东方科技集团股份有限公司 | Display panel and its detection method, display device |
CN109040624A (en) | 2018-09-06 | 2018-12-18 | 上海晔芯电子科技有限公司 | pixel circuit and read method |
CN109076179A (en) | 2016-04-06 | 2018-12-21 | 科磊股份有限公司 | Biserial parallel C CD sensor and the checking system for using sensor |
CN109816597A (en) | 2017-11-22 | 2019-05-28 | 展讯通信(上海)有限公司 | The method and apparatus for removing image GrGb noise |
US20210281794A1 (en) * | 2018-02-15 | 2021-09-09 | Sony Semiconductor Solutions Corporation | Imaging apparatus |
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US20060227228A1 (en) | 2005-02-23 | 2006-10-12 | Jung-Hyun Nam | Color image sensing device and pixel data reading method thereof |
CN109076179A (en) | 2016-04-06 | 2018-12-21 | 科磊股份有限公司 | Biserial parallel C CD sensor and the checking system for using sensor |
CN109816597A (en) | 2017-11-22 | 2019-05-28 | 展讯通信(上海)有限公司 | The method and apparatus for removing image GrGb noise |
US20210281794A1 (en) * | 2018-02-15 | 2021-09-09 | Sony Semiconductor Solutions Corporation | Imaging apparatus |
CN108398243A (en) | 2018-02-28 | 2018-08-14 | 京东方科技集团股份有限公司 | Display panel and its detection method, display device |
CN109040624A (en) | 2018-09-06 | 2018-12-18 | 上海晔芯电子科技有限公司 | pixel circuit and read method |
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